EAPSI:The Study of Novel Liquid Crystal Structures for use in Organic Solar Cell Technologies

Carlson Eric D, Broomfield CO

Investigators

Abstract

Solar cells represent a promising technology to replace fossil fuels due to the abundance of energy the sun provides to the Earth?s surface every day. Industrial solar cells currently use inorganic materials which have some advantages over organic materials; primarily the former are more efficient than the latter. However, inorganic materials are also expensive, inflexible and bulky, and are restricted to relatively small area devices. Novel organic materials can be used to overcome the cost and manufacturing limitations of current solar cell technologies. One unique organic material?a liquid crystal structure called a helical nanofilament?will be studied for its potential effectiveness in solar cell devices. This work will be conducted at KAIST in Korea with Professor Dong Ki Yoon, a world-leading expert in liquid crystal alignment techniques. Liquid crystals have been observed to have excellent organic semiconducting properties, making them a good candidate for use in organic photovoltaics. Furthermore, it has been demonstrated that bent core liquid crystals that form ?nanowire-like? helical nanofilaments can be aligned using various techniques including convection cooling, substrate surface energy modification, and nano-confinement. This offers the ability to align these filaments, and composites containing a second ?guest? material, within photovoltaic devices with relative ease, potentially leading to more efficient exciton splitting and charge transport within devices. A first look at helical nanofilaments for use in photovoltaics will be studied by placing them within an organic field effect transistor device to extract charge carrier mobility in orthogonal directions, giving insight to the efficacy of aligned helical nanofilaments in photovoltaic devices. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the National Research Foundation of Korea.